This is a good question, and I want to respond to it even though I feel such a situation should be primarily explained to you by the casino support workers.
Well, I'm going to share my point of view:
Most importantly, self-exclusion should protect vulnerable players by closing their account - leaving such account inaccessible. Or any other accounts this player has created in the meantime.
When it comes to creating another account lately, though, the situation is not always the same.
It's crucial to understand which personal information is necessary for creating such an account and which personal information the casino's system tracks automatically.
The way I understand your question, in this casino the registration email is mandatory, it seems. Though I'm not pretty sure how important the other personal details are, anyway, in some casinos, only the email and date of birth are checked upon registration. I guess you used a different email in order to pass the registration since the older email remains excluded.
That would mean the system was not able to detect you. 🤷♂️
Thus, I'm also assuming that in this casino, the system does not automatically track down all similarities or matches, on the other hand, details like the name or date of birth match will surely be detected by the KYC verification.
Well, did you ask the casino employee how it works in their casino?
If you are a vulnerable player, you should seek these answers before registering at another casino. Just in case.